Dangerousness to self or other is the major justification for involuntary psychiatric commitment in most jurisdictions. Yet scientific basis for objective assessment of this characteristic may be lacking. We will examine over a period of one year the predictive validity of psychiatric evaluations and a series of social background variables with regard to the patient's dangerousness. We will investigate how well a series of social background variables predict whether an assessment of dangerousness will be made in the lay setting by non-professionals. We will examine the ability of social background variables to predict the type of help-source (police or medical) contacted by prospective mental patients or their significant others and the speed with which they come into treatment. In the professional setting, the impact of prospective patient's mode of entry, behaviors and social background characteristics on the professional's diagnosis, dangerousness assessment, and treatment needs will be explored. Finally, implications of our findings for the current legal procedures and the assumptions underlying them will be explored. Data will be gathered through interviews as patients and accompanying relatives or friends (significant others) appear for evaluation at the psychiatric service of a major county hospital and appear for admission to a private facility. Professional evaluators will complete a rating form for each patient evaluated. Thoe who become inpatients and a similar group who are not further committed will be followed up at four-month intervals over a period of one year.